Fatal Error On Manage Page

I wanted to put a static post at the top of my blog so I dated one of my posts today’s date in the year 2010. I checked my site and it did not show up. In fact, the whole post disappeared somewhere.

I decided to nix the idea and went to my Manage / Posts page. However, this popped up:

Fatal error: Allowed memory size of 8388608 bytes exhausted (tried to allocate 315955 bytes) in /home/rantkol3/public_html/wp-includes/cache.php on line 48

All of the other Manage pages, like Pages and Uploads are fine, it’s just the post page. How can I fix it?